— Company Plans To Submit New Drug Application in Third Quarter of
2014 —

DUBLIN--(BUSINESS WIRE)--Apr. 8, 2014--
Alkermes
plc (NASDAQ: ALKS) today announced positive topline results from a
randomized, double-blind, placebo-controlled phase 3 clinical trial of
aripiprazole lauroxil in patients with schizophrenia. Patients treated
once monthly with either 441 mg or 882 mg of aripiprazole lauroxil
demonstrated statistically significant reductions from baseline in
Positive and Negative Syndrome Scale (PANSS) total scores at week 12,
compared to placebo (p<0.001 aripiprazole lauroxil 441 mg, p<0.001
aripiprazole lauroxil 882 mg), which was the prespecified primary
endpoint in the study. Based on the positive results from this phase 3
study, Alkermes plans to submit a New Drug Application (NDA) to the U.S.
Food and Drug Administration (FDA) in the third quarter of 2014.
Aripiprazole lauroxil is a new, long-acting injectable antipsychotic
agent designed to provide patients with once-monthly dosing of a
medication that, once in the body, converts to aripiprazole, a molecule
that is commercially available under the name ABILIFY®.

“These statistically significant efficacy data demonstrate aripiprazole
lauroxil’s ability to provide clinically meaningful symptom control in
patients struggling with schizophrenia,” said Henry Nasrallah, M.D.,
Chair, Department of Neurology and Psychiatry at Saint Louis University
School of Medicine. “A once-monthly version of aripiprazole with
multiple dose strengths would be a welcome addition since it would
enhance current treatment options and provide dosing flexibility. These
data come at a time when the treatment landscape for schizophrenia is
evolving; more physicians are now recognizing the benefits of
long-acting injectable antipsychotics and considering their use earlier
in disease progression.”

Data from the full analysis set showed statistically significant
improvement in PANSS total scores from baseline in both aripiprazole
lauroxil dose groups, relative to the placebo treatment group. In
addition to meeting the prespecified primary efficacy endpoint, the
study also met the prespecified key secondary endpoint of improvement on
the Clinical Global Impression – Improvement scale (CGI-I) versus
placebo at week 12 (p<0.001).

“Our goal has been to develop a differentiated long-acting injectable
product candidate responsive to the real-world needs of patients and
healthcare providers, providing the proven efficacy of aripiprazole
administered once-monthly in a ready-to-use format with multiple dosage
strengths,” stated Richard Pops, Chief Executive Officer of Alkermes.
“With these positive data in hand, we will complete the preparation of
our NDA, which we plan to submit next quarter, and continue our
preparations to bring this important new medicine to patients and
healthcare providers.”

Aripiprazole lauroxil was generally well tolerated in the phase 3 study,
and the safety profile of aripiprazole lauroxil was similar to that
reported with oral aripiprazole. The most common adverse events in the
study were insomnia, akathisia and headache.

Alkermes will present comprehensive data from the phase 3 study at an
upcoming medical meeting and submit the results for publication in a
peer-reviewed journal.

Phase 3 Study Design

The phase 3, randomized, multicenter, double-blind, placebo-controlled
study was designed to assess the efficacy, safety and tolerability of
aripiprazole lauroxil in patients experiencing acute exacerbation of
schizophrenia. The trial included adult patients who met the Diagnostic
and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision
(DSM-IV-TR®) criteria for schizophrenia and had a
PANSS total score of 70 or higher at study baseline.

A total of 623 patients were randomized to receive once-monthly
intramuscular injections of aripiprazole lauroxil 441 mg, aripiprazole
lauroxil 882 mg or placebo for 12 weeks. Following randomization,
patients received their first injection along with daily oral study drug
for the first three weeks. Patients randomized to the two aripiprazole
lauroxil treatment groups received oral aripiprazole for those initial
three weeks, while patients randomized to the placebo group received
matching oral placebo for three weeks. The primary efficacy endpoint of
the study was the change from baseline at week 12 in PANSS total score,
using an analysis of covariance (ANCOVA) with a last observation carried
forward (LOCF). The key secondary endpoint was the CGI-I score at week
12.

All participants in the double-blind portion of the study are eligible
to continue in an open-label phase and receive aripiprazole lauroxil for
an additional 12 months. The objective of the extension phase of the
study is to assess the safety and long-term durability of effect of
once-monthly aripiprazole lauroxil.

Conference Call

Alkermes will host a conference call today, April 8, 2014, at 8:00 a.m.
EDT (1:00 p.m. BST), to discuss these topline results. The conference
call may be accessed by dialing +1 888 424 8151 for U.S. callers and +1
847 585 4422 for international callers. The conference call ID number is
6037988. The conference call will also be webcast on the Investors
section of Alkermes’ website at www.alkermes.com.
In addition, a replay of the conference call will be available from
10:30 a.m. EDT (3:30 p.m. BST) on Tuesday, April 8, 2014, through 5:00
p.m. EDT (10:00 p.m. BST) on Tuesday, April 15, 2014, and may be
accessed by visiting Alkermes’ website or by dialing +1 888 843 7419 for
U.S. callers and +1 630 652 3042 for international callers. The replay
access code is 6037988.

About Aripiprazole Lauroxil

Aripiprazole lauroxil, which utilizes Alkermes’ proprietary LinkeRx®
technology, is an injectable atypical antipsychotic with one-month and
two-month formulations in development for the treatment of
schizophrenia. Once in the body, aripiprazole lauroxil converts to
aripiprazole, which is commercially available under the name ABILIFY.

About Schizophrenia and Long-Acting Medicines

Schizophrenia is a chronic, severe and disabling brain disorder. The
disease is marked by positive symptoms (hallucinations and delusions)
and negative symptoms (depression, blunted emotions and social
withdrawal), as well as by disorganized thinking. An estimated 2.4
million Americans have schizophrenia,1 with men and women
affected equally. Worldwide, it is estimated that one person in every
100 develops schizophrenia, one of the most serious types of mental
illness.

Long-acting injectable antipsychotics provide patients with blood
concentrations of active drug that remain within a therapeutic range for
an extended period of time2 and allow healthcare providers to
track when a patient does not return for a scheduled injection.3

About Alkermes

Alkermes plc is a fully integrated, global biopharmaceutical company
that applies its scientific expertise and proprietary technologies to
develop innovative medicines that improve patient outcomes. The company
has a diversified portfolio of more than 20 commercial drug products and
a substantial clinical pipeline of product candidates that address
central nervous system (CNS) disorders such as addiction, schizophrenia
and depression. Headquartered in Dublin, Ireland, Alkermes plc has an
R&D center in Waltham, Massachusetts; a research and manufacturing
facility in Athlone, Ireland; and manufacturing facilities in
Gainesville, Georgia and Wilmington, Ohio. For more information, please
visit Alkermes’ website at www.alkermes.com.

Note Regarding Forward-Looking Statements

Certain statements set forth in this press release constitute
“forward-looking statements” within the meaning of the Private
Securities Litigation Reform Act of 1995, including, but not limited to,
statements concerning: the therapeutic value, development plans and
commercial potential of aripiprazole lauroxil. The company cautions that
forward-looking statements are inherently uncertain. Although the
company believes that such statements are based on reasonable
assumptions within the bounds of its knowledge of its business and
operations, the forward-looking statements are neither promises nor
guarantees and they are necessarily subject to a high degree of
uncertainty and risk. Actual performance and results may differ
materially from those projected or suggested in the forward-looking
statements due to various risks and uncertainties. These risks and
uncertainties include, among others: regulatory submissions may not
occur or be submitted in a timely manner; adverse decisions by
regulatory authorities may occur; the company may be unable to
commercially manufacture aripiprazole lauroxil successfully; and those
risks described in the Alkermes plc Transition Report on Form 10-K for
the fiscal period ended December 31, 2013, and in other subsequent
filings made by the company with the U.S. Securities and Exchange
Commission (SEC), which are available on the SEC’s website at www.sec.gov.
The information contained in this press release is provided by the
company as of the date hereof, and, except as required by law, the
company disclaims any intention or responsibility for updating any
forward-looking information contained in this press release.

DSM-IV-TR® is a registered trademark of the American
Psychiatric Association. LinkeRx® is a registered trademark
of Alkermes Pharma Ireland Limited Corporation. ABILIFY® is a
registered trademark of Otsuka Pharmaceutical Co., Ltd.